Hydrochlorofluorocarbons (HCFC) tend to present an adverse effect on the ozone layer, and therefore, it is planned to regulate their production. HCFC are, for example, 3,3-dichloro-1,1,1,2,2-pentafluoropropane (HCFC-225ca), 1,3-dichloro-1,1,2,2,3-pentafluoropropane (HCFC-225cb), etc., but along with the regulation of HCFC, development of a compound in place of HCFC is desired.
An example of the compound in place of HCFC is 1-chloro-2,3,3-trifluoropropene (HCIC═CF—CHF2, HCFO-1233yd). HCFO-1233yd is a compound, of which the global warming potential (GWP) is small and which is useful for application to cleaning agents, solvents, refrigerants, blowing agents and aerosols.
Here, Patent Document 1 discloses a method for producing 1,1,2,2,3-pentafluoropropane (HCFC-245ca) by reacting 3-chloro-1,1,2,2-tetrafluoropropane (HCFC-244ca) with hydrogen fluoride in a vapor phase under a nitrogen stream in the presence of chromium hydroxide as a catalyst. In this method, HCFO-1233yd is produced as a by-product. Therefore, by recovering the composition obtained by the above reaction and separating from the composition, it is possible to obtain HCFO-1233yd.
HCFO-1233yd obtained by the above method may be one obtainable as a composition which comprises 1-chloro-3,3-difluoro-1-propyne produced as a by-product in the production step for HCFO-1233yd and an oxide formed by oxidation of HCFO-1233yd by oxygen in air.
At the time of using the above composition containing HCFO-1233yd, as a cleaning agent, solvent, refrigerant, blowing agent or aerosol, if 1-chloro-3,3-difluoro-1-propyne is contained in the composition at a high concentration, it may cause various problems on reliability and performance. In order to suppress such undesirable effects, it is preferred to minimize the content of 1-chloro-3,3-difluoro-1-propyne.
Further, at the time of using the above composition containing HCFO-1233yd in the above application, if the oxide is contained in the composition at a high concentration, it may cause problems such as deterioration of stability and formation of an acidifying agent. In order to suppress such undesirable effects, it is preferred to minimize the content of the oxide.
However, Patent Document 1 fails to disclose a method for effectively removing 1-chloro-3,3-difluoro-1-propyne and the oxide from the composition containing HCFO-1233yd.